A highly selective multi-zero millimeter wave bandpass filter

Abstract

The application discloses a high-selectivity multi-zero-point millimeter wave band-pass filter. Electromagnetic waves are transmitted to resonator 1 through an input feed line, then transmitted to resonator 2 through mixed coupling and transmitted to resonator 4 through magnetic coupling. The electromagnetic waves are transmitted from resonator 2 to resonator 3 through a first connecting metal, and the coupling at this time is electric coupling; the electromagnetic waves are transmitted from resonator 3 to resonator 4 through mixed coupling and then transmitted to an output feed line. The multi-zero-point is caused due to the introduction of electric coupling between resonator 2 and resonator 3 and the introduction of mixed coupling between resonator 1, resonator 2, resonator 3 and resonator 4. The application is based on lumped-distributed combined structure and IPD technology, and a MIM capacitor is introduced to realize the miniaturization of the filter size.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wireless communication, and relates to a high-selectivity multi-zero-point millimeter wave band-pass filter, which is a structure combining lumped and distributed based on IPD technology and has a 5G-N257 frequency band radio frequency band-pass filter. BACKGROUND

[0002] With the development of 5G wireless communication, millimeter wave technology has received extensive attention. One of the most significant differences between 5G millimeter wave systems and 2G-4G radio frequency front-end modules (FEMs) is the higher requirement for system integration and reliability. Therefore, it is necessary to integrate passive devices and active devices onto a single chip. Among these passive devices, band-pass filters (BPFs) are crucial to maintaining the overall performance of the system.

[0003] In 5G millimeter wave systems, band-pass filters (BPFs) play a key role to ensure high performance and reliability, which are more important in 2G-4G radio frequency front-end modules (FEMs) because of the significant increase in operating frequency. The typical frequency range for 5G millimeter wave applications is 24.25 to 29.5 GHz, which requires BPFs to have a 5GHz bandwidth, much wider than in 4G systems. However, commonly used surface / body acoustic wave (SAW / BAW) filters are not suitable for 5G millimeter wave applications because of their limitations in high-frequency and wide-band performance. Therefore, advanced technologies such as miniaturization, high-Q design, and new materials are needed to meet the strict and challenging performance requirements of 5G BPFs. Despite these challenges, BPFs are still essential components to achieve high-performance, reliable, and cost-effective 5G millimeter wave communication systems.

[0004] One important benefit of applying IPD technology to 5G is the ability to achieve higher integration on a single chip. IPD technology makes it possible to integrate many passive components onto a single substrate, reducing system costs while improving reliability and stability. These advantages make IPD technology have broad application prospects in 5G millimeter wave systems, including but not limited to radio frequency front-ends, antennas, and passive devices.

[0005] Cross-coupled filters are used to generate transmission zeros in the stopband. Transmission zeros are important for suppressing interfering signals from adjacent channels and spurious signals that can be generated by the circuit. An Nth-order cross-coupled bandpass filter with nonadjacent resonators can introduce up to N-2 transmission zeros. In addition to cross-coupling techniques, there are many other bandpass filter design methods that can introduce transmission zeros. For example, half-wavelength resonators can be used to generate transmission zeros at specified frequency points, reverse parallel-coupled lines can be used to generate transmission zeros, branch-line structures can be used to generate transmission zeros, defect ground structures can be used to generate transmission zeros, and zero-coupling techniques or feeding techniques can be used to generate transmission zeros. These techniques can introduce transmission zeros at specified frequency points to improve the passband selectivity and out-of-band suppression of the bandpass filter. The introduction of these transmission zero techniques has important application value for improving the overall performance of the filter. However, each technique has its own drawbacks.

[0006] Cross-coupling techniques can increase the size and complexity of the filter, as they require the addition of extra coupling elements between nonadjacent resonators or changes to the layout of the resonators. Using half-wavelength resonators to generate transmission zeros at specified frequency points requires precise control of the lengths and positions of the resonators, and can increase the size and complexity of the filter. Using reverse parallel-coupled lines to generate transmission zeros requires consideration of the termination type and load type of the reverse parallel-coupled lines, and can introduce additional losses and spurious effects. Using branch-line structures to generate transmission zeros requires the addition of branch-line elements to the transmission lines, which can affect the impedance matching and stability of the filter. Using defect ground structures to generate transmission zeros requires cutting out defect regions on the ground plane, which can increase the radiation loss and sensitivity of the filter. Using zero-coupling techniques or feeding techniques to generate transmission zeros requires the addition of extra elements to the filter or changes to the feeding method, which can limit the application range and flexibility of the filter. SUMMARY

[0007] The purpose of the present application is to overcome the above-mentioned difficulties and provide a high-selectivity multi-zero-point millimeter wave bandpass filter based on a combination of lumped and distributed structures, which has a small bandwidth, a small area, and a high-selectivity bandpass filter to meet the requirements of the 5G-N257 frequency band communication system.

[0008] The filter of the present application comprises, from top to bottom, a first metal layer M8 (1), a first dielectric layer P8 (2), a second metal layer M7 (3), a second dielectric layer P7 (4), a third metal layer M6 (5), a third dielectric layer P6 (6), a fourth metal layer M5 (7), a fourth dielectric layer P5 (8), a fifth metal layer M4 (9), a fifth dielectric layer P4 (10), and a ground layer M3 (11).

[0009] The first metal layer M8(1) includes a first upper layer metal (1-1), a second upper layer metal (1-2), a first connecting metal (1-3), an input feed line (12), an output feed line (13), a first upper layer coupling line (1-4), a second upper layer coupling line (1-5), a first ground plate (1-6); the first upper layer metal (1-1) is connected to the second upper layer metal (1-2) through the first connecting metal (1-3); the first upper layer coupling line (1-4) is connected to the end of the first upper layer metal (1-1); the second upper layer coupling line (1-5) is connected to the end of the second upper layer metal (1-2);

[0010] The first upper layer metal (1-1) and the second upper layer metal (1-2) are axisymmetric structures;

[0011] The second metal layer M7(3) includes a first lower layer metal (3-1), a second lower layer metal (3-2), a first lower layer coupling line (3-3), a second lower layer coupling line (3-4), an input feed line patch (3-5), an output feed line patch (3-6), a second ground plate (3-7); the first lower layer coupling line (3-3) is connected to the end of the first lower layer metal (3-1); the second lower layer metal (3-2) is connected to the end of the second lower layer metal (3-2);

[0012] The first lower layer metal (3-1) and the second lower layer metal (3-2) are axisymmetric structures, and a gap is left between them; the first lower layer metal (3-1) and the second upper layer metal (1-2) have the same structure;

[0013] The third metal layer M6(5) includes a third upper layer metal (5-1), a fourth upper layer metal (5-2), a third ground plate (5-3), a third upper layer coupling line (5-4), a fourth upper layer coupling line (5-5); the third upper layer coupling line (5-4) is connected to the end of the third upper layer metal (5-1); the fourth upper layer coupling line (5-5) is connected to the end of the fourth upper layer metal (5-2);

[0014] The third upper layer metal (5-1) and the fourth upper layer metal (5-2) are axisymmetric structures, and a gap is left between them; the third upper layer metal (5-1) is the structure of the first upper layer metal (1-1) rotated 180° clockwise, but the size is different;

[0015] The fourth metal layer M5 (7) comprises a third lower metal (7-1), a fourth lower metal (7-2), a fourth ground plate (7-3), a third lower coupling line (7-4), and a fourth lower coupling line (7-5); the third lower coupling line (7-4) is connected with the end of the third lower metal (7-1); and the fourth lower coupling line (7-5) is connected with the end of the fourth lower metal (7-2);

[0016] The third lower metal (7-1) and the fourth lower metal (7-2) are axially symmetrical structures and have a gap therebetween; and the third lower metal (7-1) and the fourth upper metal (5-2) have the same structure;

[0017] The fifth metal layer M4 (9) comprises a fifth ground plate (9-1);

[0018] The first upper metal (1-1), the first lower metal (3-1), and the first metallized via (14) penetrating through the first dielectric layer P8 (2) constitute a second lumped distributed combined resonator; the second upper metal (1-2), the second lower metal (3-2), and the second metallized via (15) penetrating through the first dielectric layer P8 (2) constitute a third lumped distributed combined resonator; and the first connecting metal (1-3) is used for connecting the second lumped distributed combined resonator and the third lumped distributed combined resonator;

[0019] The third upper metal (5-1), the third lower metal (7-1), and the third metallized via (16) penetrating through the third dielectric layer P6 (6) constitute a first lumped distributed combined resonator; and the fourth upper metal (5-2), the fourth lower metal (7-2), and the fourth metallized via (17) penetrating through the third dielectric layer P6 (6) constitute a fourth lumped distributed combined resonator;

[0020] The first upper coupling line (1-4) and the third lower coupling line (7-4) are coupled and connected, the first lower coupling line (3-3) and the third upper coupling line (5-4) are coupled and connected, so as to realize the coupling between the first lumped distributed combined resonator and the second lumped distributed combined resonator;

[0021] The second upper coupling line (1-5) and the fourth lower coupling line (7-5) are coupled and connected, and the second lower coupling line (3-4) and the fourth upper coupling line (5-5) are coupled and connected, so as to realize the coupling between the third lumped distributed combined resonator and the fourth lumped distributed combined resonator;

[0022] The input feed line (12) and the output feed line (13) are connected with the input feed line patch (3-5) and the output feed line patch (3-6) through the fifth metallized via (18) and the sixth metallized via (19) penetrating through the first dielectric layer P8 (2), respectively.

[0023] The first ground plate (1-6), the second ground plate (3-7), the third ground plate (5-3), the fourth ground plate (7-3), and the fifth ground plate (9-1) are connected with the ground layer M3 (11) through the ground metallization vias penetrating the first dielectric layer P8 (2), the second dielectric layer P7 (4), the third dielectric layer P6 (6), the fourth dielectric layer P5 (8), and the fifth dielectric layer P4 (10);

[0024] The input feed patch (3-5) and the output feed patch (3-6) are connected with the third upper metal (5-1) and the fourth upper metal (5-2) through the seventh metallization via (20) and the eighth metallization via (21) penetrating the second dielectric layer P7 (4) respectively;

[0025] Preferably, the first upper metal (1-1) is in a spiral structure, which comprises the first upper microstrip line (1-1-1), the second upper microstrip line (1-1-2), and the third upper microstrip line (1-1-3) from inside to outside;

[0026] The first upper metal (1-1) and the first lower metal (3-1) constitute the MIM capacitor C32; the second upper metal (1-2) and the second lower metal (3-2) constitute the MIM capacitor C33; the third upper metal (5-1) and the third lower metal (7-1) constitute the MIM capacitor C31; the fourth upper metal (5-2) and the fourth lower metal (7-2) constitute the MIM capacitor C34; the center frequency is adjusted by adjusting the sizes of the capacitors C31 and C34; the center frequency is adjusted by adjusting the sizes of the capacitors C32 and C33;

[0027] The bandwidth is adjusted by adjusting the mixed coupling between the first lumped distributed combined resonator and the second lumped distributed combined resonator, the mixed coupling between the third lumped distributed combined resonator and the fourth lumped distributed combined resonator, the electric coupling between the second lumped distributed combined resonator and the third lumped distributed combined resonator, and the magnetic coupling between the first lumped distributed combined resonator and the fourth lumped distributed combined resonator;

[0028] Working principle:

[0029] The electromagnetic wave is transmitted to the first lumped distributed combined resonator through the input feed line, then transmitted to the second lumped distributed combined resonator through the mixed coupling and transmitted to the fourth lumped distributed combined resonator through the magnetic coupling. The electromagnetic wave is transmitted from the second lumped distributed combined resonator to the third lumped distributed combined resonator through the first connecting metal at this time, the coupling is electric coupling, the electromagnetic wave is transmitted from the third lumped distributed combined resonator to the fourth lumped distributed combined resonator through the mixed coupling and then transmitted to the output feed line. The introduction of the electric coupling between the second lumped distributed combined resonator and the third lumped distributed combined resonator and the mixed coupling between the first lumped distributed combined resonator, the second lumped distributed combined resonator, the third lumped distributed combined resonator and the fourth lumped distributed combined resonator leads to the generation of multiple zero points.

[0030] The beneficial effects of the present application are:

[0031] (1) Based on the lumped distributed combined structure and the IPD technology, the MIM capacitor is introduced to realize the miniaturization of the filter size.

[0032] (2) The filter of the present application can realize a small bandwidth of 3GHz in the 5G millimeter wave frequency band.

[0033] (3) The filter of the present application is not only very compact in size, but also has high frequency selectivity and good passband performance. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 Fig. 1 is a structural schematic diagram of the filter of the present application; (a) is a top view of the first metal layer M8+the first dielectric layer P8, (b) is a top view of the second metal layer M7+the second dielectric layer P7, (c) is a top view of the third metal layer M6+the third dielectric layer P6, (d) is a top view of the fourth metal layer M5+the fourth dielectric layer P5, (e) is a top view of the fifth metal layer M4+the fifth dielectric layer P4, (f) is a top view of the ground layer M3, and (g) is a side view of the filter;

[0035] Figure 2 Fig. 2 is a structural schematic diagram of the first to fourth lumped distributed combined resonators;

[0036] Figure 3 (a) is a size structure diagram of the first upper metal, the second upper metal, the first upper coupling line and the second upper coupling line;

[0037] Figure 3 (b) is a size structure diagram of the third upper metal, the fourth upper metal, the third upper coupling line and the fourth upper coupling line;

[0038] Figure 4 Fig. 3 is an equivalent circuit schematic diagram of the filter of the present application;

[0039] Figure 5 S-parameter plot near the passband of the filter of the present application;

[0040] Figure 6 S-parameter simulation plot of the stopband rejection of the filter of the present application;

[0041] Figure 7 Performance comparison plot of the filter of the present application and a commercial filter.

[0042] wherein K refers to magnetic coupling; C14, 24, 110, 210 are electrical coupling. DETAILED DESCRIPTION

[0043] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "length", "width", "thickness", "upper", "lower", "left", "right", "clockwise", "counterclockwise", "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0044] In the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] As Figures 1-3 The filter of the present application comprises, from top to bottom, a first metal layer M81, a first dielectric layer P82, a second metal layer M73, a second dielectric layer P74, a third metal layer M65, a third dielectric layer P66, a fourth metal layer M57, a fourth dielectric layer P58, a fifth metal layer M49, a fifth dielectric layer P410, and a ground layer M311.

[0046] The first metal layer M81 includes a first upper layer metal 1-1, a second upper layer metal 1-2, a first connecting metal 1-3, an input feed line 12, an output feed line 13, a first upper layer coupling line 1-4, a second upper layer coupling line 1-5, a first ground plate 1-6; the first upper layer metal 1-1 is connected to the second upper layer metal 1-2 through the first connecting metal 1-3; the first upper layer metal 1-1 is in a spiral structure, which includes a first upper layer microstrip line 1-1-1, a second upper layer microstrip line 1-1-2, and a third upper layer microstrip line 1-1-3 from inside to outside, and the first upper layer microstrip line 1-1-1 is connected to the first connecting metal 1-3 at the outside of the second upper layer microstrip line 1-1-2; the first upper layer coupling line 1-4 is connected to the outside end of the first upper layer metal 1-1; the first upper layer metal 1-1 and the second upper layer metal 1-2 are in an axisymmetric structure; the second upper layer coupling line 1-5 is connected to the outside end of the second upper layer metal 1-2;

[0047] The second metal layer M73 includes a first lower layer metal 3-1, a second lower layer metal 3-2, a first lower layer coupling line 3-3, a second lower layer coupling line 3-4, an input feed line patch 3-5, an output feed line patch 3-6, and a second ground plate 3-7; the first lower layer metal 3-1 has the same structure as the second upper layer metal 1-2; the first lower layer coupling line 3-3 is connected to the outside end of the first lower layer metal 3-1; the first lower layer metal 3-1 and the second lower layer metal 3-2 are in an axisymmetric structure, and a gap is left between them; the second lower layer metal 3-2 is connected to the outside end of the second lower layer metal 3-2;

[0048] The inside port of the first upper layer metal 1-1 is connected to the inside port of the first lower layer metal 3-1 through a first metallized via hole 14; the inside port of the second upper layer metal 1-2 is connected to the inside port of the second lower layer metal 3-2 through a second metallized via hole 15;

[0049] The third metal layer M65 includes a third upper layer metal 5-1, a fourth upper layer metal 5-2, a third ground plate 5-3, a third upper layer coupling line 5-4, and a fourth upper layer coupling line 5-5; the third upper layer metal 5-1 is a structure obtained by rotating the first upper layer metal 1-1 by 180° clockwise; the third upper layer coupling line 5-4 is connected to the outside end of the third upper layer metal 5-1; the third upper layer metal 5-1 and the fourth upper layer metal 5-2 are in an axisymmetric structure, and a gap is left between them; the fourth upper layer coupling line 5-5 is connected to the outside end of the fourth upper layer metal 5-2;

[0050] The fourth metal layer M57 comprises a third lower metal 7-1, a fourth lower metal 7-2, a fourth ground plate 7-3, a third lower coupling line 7-4, and a fourth lower coupling line 7-5; the third lower metal 7-1 has the same structure as the fourth upper metal 5-2; the third lower coupling line 7-4 is connected with the outer side end of the third lower metal 7-1; the third lower metal 7-1 and the fourth lower metal 7-2 are in an axisymmetric structure and have a gap therebetween; the fourth lower coupling line 7-5 is connected with the outer side end of the fourth lower metal 7-2;

[0051] The inner side port of the third upper metal 5-1 is connected with the inner side port of the third lower metal 7-1 through a third metallized via hole 16; the inner side port of the fourth upper metal 5-2 is connected with the inner side port of the fourth lower metal 7-2 through a fourth metallized via hole 17;

[0052] The fifth metal layer M49 comprises a fifth ground plate 9-1;

[0053] A second lumped distributed combined resonator is composed of the first upper metal 1-1, the first lower metal 3-1, and a first metallized via hole 14 penetrating through the first dielectric layer P82; a third lumped distributed combined resonator is composed of the second upper metal 1-2, the second lower metal 3-2, and a second metallized via hole 15 penetrating through the first dielectric layer P82; the first connecting metal 1-3 is used for connecting the second lumped distributed combined resonator and the third lumped distributed combined resonator;

[0054] A first lumped distributed combined resonator is composed of the third upper metal 5-1, the third lower metal 7-1, and a third metallized via hole 16 penetrating through the third dielectric layer P66; a fourth lumped distributed combined resonator is composed of the fourth upper metal 5-2, the fourth lower metal 7-2, and a fourth metallized via hole 17 penetrating through the third dielectric layer P66;

[0055] The first upper coupling line 1-4 is coupled and connected with the third lower coupling line 7-4, and the first lower coupling line 3-3 is coupled and connected with the third upper coupling line 5-4, so as to realize the coupling between the first lumped distributed combined resonator and the second lumped distributed combined resonator;

[0056] The second upper coupling line 1-5 is coupled and connected with the fourth lower coupling line 7-5, and the second lower coupling line 3-4 is coupled and connected with the fourth upper coupling line 5-5, so as to realize the coupling between the third lumped distributed combined resonator and the fourth lumped distributed combined resonator;

[0057] The input feed line 12 and the output feed line 13 are connected with the input feed line patch 3-5 and the output feed line patch 3-6 through a fifth metallized via hole 18 and a sixth metallized via hole 19 penetrating through the first dielectric layer P82, respectively.

[0058] The first ground plate 1-6, the second ground plate 3-7, the third ground plate 5-3, the fourth ground plate 7-3, the fifth ground plate 9-1 are connected with the ground layer M311 through the ground metallization via penetrating the first dielectric layer P82, the second dielectric layer P74, the third dielectric layer P66, the fourth dielectric layer P58, the fifth dielectric layer P410;

[0059] The input feed line patch 3-5, the output feed line patch 3-6 are connected with the third upper layer metal 5-1, the fourth upper layer metal 5-2 through the seventh metallization via 20, the eighth metallization via 21 penetrating the second dielectric layer P74 respectively;

[0060] The above filter circuit is equivalent, see Figure 4 :

[0061] The input feed line 12, the output feed line 13 are equivalent to inductors L0 and L41; the first upper layer metal 1-1, the first lower layer metal 3-1 and the first metallization via 14 are equivalent to inductors L13, L14, L23, L24 and L32; the second upper layer metal 1-2, the second lower layer metal 3-2 and the second metallization via 15 are equivalent to inductors L15, L16, L25, L26 and L34; the first connection metal 1-3 is equivalent to inductor L33;

[0062] The third upper layer metal 5-1, the third lower layer metal 7-1 and the third metallization via 16 are equivalent to inductors L11, L12, L21, L22 and L31; the fourth upper layer metal 5-2, the fourth lower layer metal 7-2 and the fourth metallization via 17 are equivalent to inductors L17, L18, L27, L28 and L35;

[0063] The first upper layer metal 1-1 and the first lower layer metal 3-1 constitute MIM capacitor C32 as different layers;

[0064] The second upper layer metal 1-2 and the second lower layer metal 3-2 constitute MIM capacitor C33 as different layers;

[0065] The third upper layer metal 5-1 and the third lower layer metal 7-1 constitute MIM capacitor C31 as different layers;

[0066] The fourth upper layer metal 5-2 and the fourth lower layer metal 7-2 constitute MIM capacitor C34 as different layers;

[0067] The first upper layer metal 1-1 and the ground layer M311 constitute ground capacitor C15 as different layers;

[0068] The first lower layer metal 3-1 and the ground layer M311 constitute ground capacitor C25 as different layers;

[0069] The second upper metal 1-2 and the ground layer M311 form a ground capacitance C17 as different layers;

[0070] The second lower metal 3-2 and the ground layer M311 form a ground capacitance C27 as different layers;

[0071] The third upper metal 5-1 and the ground layer M311 form a ground capacitance C11 as different layers;

[0072] The third lower metal 7-1 and the ground layer M311 form a ground capacitance C21 as different layers;

[0073] The fourth upper metal 5-2 and the ground layer M311 form a ground capacitance C111 as different layers;

[0074] The fourth lower metal 7-2 and the ground layer M311 form a ground capacitance C211 as different layers;

[0075] The first upper coupling line 1-4 and the third lower coupling line 7-4 form a MIM capacitance C14 as different layers;

[0076] The first upper coupling line 1-4 and the ground layer M311 form a ground capacitance C12 as different layers;

[0077] The third lower coupling line 7-4 and the ground layer M311 form a ground capacitance C13 as different layers;

[0078] The second upper coupling line 1-5 and the fourth lower coupling line 7-5 form a MIM capacitance C110 as different layers;

[0079] The second upper coupling line 1-5 and the ground layer M311 form a ground capacitance C18 as different layers;

[0080] The fourth lower coupling line 7-5 and the ground layer M311 form a ground capacitance C19 as different layers;

[0081] The first lower coupling line 3-3 and the third upper coupling line 5-4 form a MIM capacitance C24 as different layers;

[0082] The first lower coupling line 3-3 and the ground layer M311 form a ground capacitance C22 as different layers;

[0083] The third upper coupling line 5-4 and the ground layer M311 form a ground capacitance C23 as different layers;

[0084] The second lower coupling line 3-4 and the fourth upper coupling line 5-5 form a MIM capacitance C210 as different layers;

[0085] The second lower coupling line 3-4 and the ground layer M311 form a ground capacitance C28 as different layers;

[0086] The fourth upper layer coupling line 5-5 and the ground layer M311 form a grounding capacitor C29;

[0087] The input feed line 12 and the ground layer M311 form a grounding capacitor C0;

[0088] The output feed line 13 and the ground layer M311 form a grounding capacitor C41;

[0089] The first connection metal 1-3 and the ground layer M311 form a grounding capacitor C16 and a grounding capacitor C26;

[0090] The first upper layer metal 1-1 and the first lower layer metal 3-1 form a MIM capacitor C32; the second upper layer metal 1-2 and the second lower layer metal 3-2 form a MIM capacitor C33; the third upper layer metal 5-1 and the third lower layer metal 7-1 form a MIM capacitor C31; the fourth upper layer metal 5-2 and the fourth lower layer metal 7-2 form a MIM capacitor C34; the center frequency is regulated by adjusting the sizes of the capacitors C31 and C34; the center frequency is regulated by adjusting the sizes of the capacitors C32 and C33;

[0091] The bandwidth is regulated by adjusting the mixed coupling between the first lumped distributed combined resonator and the second lumped distributed combined resonator; the bandwidth is regulated by adjusting the mixed coupling between the third lumped distributed combined resonator and the fourth lumped distributed combined resonator; the bandwidth is regulated by adjusting the electric coupling between the second lumped distributed combined resonator and the third lumped distributed combined resonator; the bandwidth is regulated by adjusting the magnetic coupling between the first lumped distributed combined resonator and the fourth lumped distributed combined resonator.

[0092] Table 1: Size of each element of the filter of the present application (unit: um)

[0093] L1 L2 L3 L4 L5 L6 W1 W2 W3 W4 W5 202 103 126 239 103 144.5 200 40 120 40 55

[0094] Figure 5 The figure is the passband S parameter simulation diagram of the filter, wherein the center frequency is 28 GHz, the 3dB bandwidth is 3 GHz, the in-band insertion loss is-3.4dB, and the return loss is less than-20dB.

[0095] Figure 6 The figure is the stopband simulation of the filter, and it can be seen that the stopband suppression of 20dB of the filter of the present application can reach 80GHz 2.857f0.

[0096] Figure 7 The figure is the comparison between the filter of the present application and a commercial filter, and the advantage is that the size is small, and wide stopband suppression is realized under the condition of comparable selectivity.

[0097] Table 1: Comparison of the performance of the filter of the present application and the existing millimeter wave bandpass filter

[0098]

[0099]

[0100] Table 1 shows the comparison of the filter of the present application with four other millimeter wave bandpass filters, and Table 2 shows the comparison of the filter of the present application with a commercial filter from Mini-Circuits. From the tables, it can be seen that the filter of the present application has the advantages of small bandwidth, small size, excellent selectivity and wide out-of-band rejection.

Claims

1. A high-selectivity multi-zero-point millimeter wave bandpass filter, sequentially comprising, from top to bottom, a first metal layer M8 (1), a first dielectric layer P8 (2), a second metal layer M7 (3), a second dielectric layer P7 (4), a third metal layer M6 (5), a third dielectric layer P6 (6), a fourth metal layer M5 (7), a fourth dielectric layer P5 (8), a fifth metal layer M4 (9), a fifth dielectric layer P4 (10), and a ground layer M3 (11); characterized in that: the first metal layer M8 (1) comprises a first upper layer metal (1-1), a second upper layer metal (1-2), a first connecting metal (1-3), an input feed line (12), an output feed line (13), a first upper layer coupling line (1-4), a second upper layer coupling line (1-5), and a first ground plate (1-6); the first upper layer metal (1-1) is connected to the second upper layer metal (1-2) through the first connecting metal (1-3); the first upper layer coupling line (1-4) is connected to an end of the first upper layer metal (1-1); and the second upper layer coupling line (1-5) is connected to an end of the second upper layer metal (1-2); the first upper layer metal (1-1) and the second upper layer metal (1-2) are axially symmetrical structures; the second metal layer M7 (3) comprises a first lower layer metal (3-1), a second lower layer metal (3-2), a first lower layer coupling line (3-3), a second lower layer coupling line (3-4), an input feed line patch (3-5), an output feed line patch (3-6), and a second ground plate (3-7); the first lower layer coupling line (3-3) is connected to an end of the first lower layer metal (3-1); and the second lower layer metal (3-2) is connected to an end of the second lower layer metal (3-2); the first lower layer metal (3-1) and the second lower layer metal (3-2) are axially symmetrical structures, and a gap is left between them; the first lower layer metal (3-1) has the same structure as the second upper layer metal (1-2); the third metal layer M6 (5) comprises a third upper layer metal (5-1), a fourth upper layer metal (5-2), a third ground plate (5-3), a third upper layer coupling line (5-4), and a fourth upper layer coupling line (5-5); the third upper layer coupling line (5-4) is connected to an end of the third upper layer metal (5-1); and the fourth upper layer coupling line (5-5) is connected to an end of the fourth upper layer metal (5-2); the third upper layer metal (5-1) and the fourth upper layer metal (5-2) are axially symmetrical structures, and a gap is left between them; and the third upper layer metal (5-1) is a structure obtained by rotating the first upper layer metal (1-1) clockwise by 180°. ​ ​ ​ ​ ​ ​ The fourth metal layer M5 (7) comprises a third lower metal (7-1), a fourth lower metal (7-2), a fourth ground plate (7-3), a third lower coupling line (7-4), and a fourth lower coupling line (7-5); the third lower coupling line (7-4) is connected with the end of the third lower metal (7-1); and the fourth lower coupling line (7-5) is connected with the end of the fourth lower metal (7-2). The third lower metal (7-1) and the fourth lower metal (7-2) are axially symmetrical structures and have a gap therebetween; and the third lower metal (7-1) and the fourth upper metal (5-2) have the same structure. The fifth metal layer M4 (9) comprises a fifth ground plate (9-1). A second lumped distributed combined resonator is formed by the first upper metal (1-1), the first lower metal (3-1), and a first metalized via (14) penetrating through the first dielectric layer P8 (2); a third lumped distributed combined resonator is formed by the second upper metal (1-2), the second lower metal (3-2), and a second metalized via (15) penetrating through the first dielectric layer P8 (2); and the first connecting metal (1-3) is used for connecting the second lumped distributed combined resonator and the third lumped distributed combined resonator. A first lumped distributed combined resonator is formed by the third upper metal (5-1), the third lower metal (7-1), and a third metalized via (16) penetrating through the third dielectric layer P6 (6); and a fourth lumped distributed combined resonator is formed by the fourth upper metal (5-2), the fourth lower metal (7-2), and a fourth metalized via (17) penetrating through the third dielectric layer P6 (6). The first upper coupling line (1-4) and the third lower coupling line (7-4) are coupled and connected, the first lower coupling line (3-3) and the third upper coupling line (5-4) are coupled and connected, so as to realize the coupling between the first lumped distributed combined resonator and the second lumped distributed combined resonator. The second upper coupling line (1-5) and the fourth lower coupling line (7-5) are coupled and connected, and the second lower coupling line (3-4) and the fourth upper coupling line (5-5) are coupled and connected, so as to realize the coupling between the third lumped distributed combined resonator and the fourth lumped distributed combined resonator.

2. The band-pass filter according to claim 1, characterized in that The input feed line (12) and the output feed line (13) are connected with the input feed line patch (3-5) and the output feed line patch (3-6) through a fifth metalized via (18) and a sixth metalized via (19) penetrating through the first dielectric layer P8 (2), respectively.

3. The band-pass filter of claim 1, wherein, The first ground plate (1-6), the second ground plate (3-7), the third ground plate (5-3), the fourth ground plate (7-3), and the fifth ground plate (9-1) are connected with the ground layer M3 (11) through a ground metalized via penetrating through the first dielectric layer P8 (2), the second dielectric layer P7 (4), the third dielectric layer P6 (6), the fourth dielectric layer P5 (8), and the fifth dielectric layer P4 (10).

4. The band-pass filter of claim 1, wherein, The input feed patch (3-5) and the output feed patch (3-6) are connected with the third upper layer metal (5-1) and the fourth upper layer metal (5-2) respectively through the seventh metallized via (20) and the eighth metallized via (21) penetrating the second dielectric layer P7 (4).

5. The bandpass filter of claim 1, wherein, The first upper layer metal (1-1) is in a spiral structure, which comprises the first upper layer microstrip line (1-1-1), the second upper layer microstrip line (1-1-2) and the third upper layer microstrip line (1-1-3) from inside to outside.

6. The bandpass filter of claim 1, wherein, The first upper layer metal (1-1) and the first lower layer metal (3-1) constitute the MIM capacitor C32; the second upper layer metal (1-2) and the second lower layer metal (3-2) constitute the MIM capacitor C33; the third upper layer metal (5-1) and the third lower layer metal (7-1) constitute the MIM capacitor C31; the fourth upper layer metal (5-2) and the fourth lower layer metal (7-2) constitute the MIM capacitor C34; the center frequency is regulated by adjusting the sizes of the capacitors C31 and C34; the center frequency is regulated by adjusting the sizes of the capacitors C32 and C33.

7. The bandpass filter of claim 1, wherein, The bandwidth is regulated by adjusting the mixed coupling between the first lumped distributed combined resonator and the second lumped distributed combined resonator, the mixed coupling between the third lumped distributed combined resonator and the fourth lumped distributed combined resonator, the electric coupling between the second lumped distributed combined resonator and the third lumped distributed combined resonator, and the magnetic coupling between the first lumped distributed combined resonator and the fourth lumped distributed combined resonator.

8. The all-pass filter according to any one of claims 1 to 7, characterized in that The electromagnetic wave is transmitted to the first lumped distributed combined resonator through the input feed line, then transmitted to the second lumped distributed combined resonator through the mixed coupling and to the fourth lumped distributed combined resonator through the magnetic coupling; The electromagnetic wave is transmitted from the second lumped distributed combined resonator to the third lumped distributed combined resonator through the first connecting metal, and the coupling at this time is electric coupling; the electromagnetic wave is transmitted from the third lumped distributed combined resonator to the fourth lumped distributed combined resonator through the mixed coupling and then to the output feed line; The introduction of the electric coupling between the second lumped distributed combined resonator and the third lumped distributed combined resonator and the mixed coupling between the first lumped distributed combined resonator, the second lumped distributed combined resonator, the third lumped distributed combined resonator and the fourth lumped distributed combined resonator leads to the generation of multiple zero points.

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